Transformer-tap changer



Sept. 6,1927. 5. HOREUCK ,271

TRANSFORMER TAP CHANGER Filed Feb. 12, 1923 Patented Sept. 6, 1927.

UNITED STATES' 1,641,271 PATENT OFFICE- SAMUEL HORELICK, OF PITTSRURGH,PENNSYLVANIA, ASSIGNOR TO ZPITTSBURGH TRANSFORMER COMPANY; A CORPORATIONOF PENNSYLVANIA.

TRANSFORMER-TAP CHANGER.

' Application filed February 12, 1923. Serial No. 618,448.

This invention relates to transformers and particularly to transformersimmersed in oil in a containing tank. It is sometimes desirable inconnection with such transformers to connect into circuit more or lessof the winding, primary or secondary, according to the service desired.For this purpose certain points of the winding are-carried out by tapconnections so that the length of the winding may be varied byconnecting the leads to different taps. In an oil cooled transformer thetap terminals are preferably within the tank and are therefore difiicultof access and to change the connections 16 it is necessary to open thetank and reach down within it.

The object of this invention is to avold this necessity of opening thetank to change the tap connections. In the apparatus of this inventionthe tap terminals are kept within the tank and control means for them isextended out through the cover so that the operator at the outside ofthe tank may make the shift from one tap to the other without openingthe tank.

Further objects of'the invention particularly in providing tap changingmeans which willbe simple and durable in form.

and accurate in operation will appear from the following descriptiontaken in connection with the accompanying drawings, in which Fig. 1 is avertical sectional view through the top of a; transformer tank showingthe tap changing means in elevation,

Fig. 2 is an elevation of the tap changing device with certain of theconnected parts shown in section,

Fig. 3 is a plan view of the slab support for the top terminals, I Fig.4 is a plan View of the control means outside of the tank, and

Fig. 5 is a diagram illustrating the cir cuits.

In the specific embodiment of the inven tion shown in the drawings atransformer tank 4 having a top 5 contains a transformer having a core 6and winding 7. Extending upward-from a frame 8 supporting the core arebolts 10 and supported by these bolt" is a supporting slab 11 ofinsulating material such as asbestos ebony for the tap terminals 12, 13and 14, these tap terminals being connected by conductors 12', 13 and14' to desired portions of the secondary. winding. The other end of thesecondary winding 1s serted. between the leaves 23 of terminals 7 12, 13or 14. Each of these terminals is rigidly fastened to the slab 11 andpasses therethroughas a downwardly extending bolt 24 adapted to beconnected to the corresponding lead 12', 13 or 14. The rod 20 isslidably mounted in a bushing 25 (Fig. 2) passing through the slab 11 sothat upon lifting the casting 21 the latter may be turned around theaxis of the rod 20 so as to bring the knife 22 in position to fit intoeither of the terminals 12, 13 or 14 as desired and thus connect the rod20 and lead 17 in circuit with the selected tap of the secondarywinding. 1

To permit the knife switch 22 to be moved from the outside of the tankthe rod 20 above the casting 21 is bolted at 26 to an insulating block27 connected at its upper end 28 to a rod 29 extending up through thetank cover 5 and car ing at its upper end a handle device 31. he tanktop 5 is provided with a flanged opening for the rod 29, the flange .32of this opening having fitted within it a block 33 welded in place asindicated at 34 and recessed at the center to contain the packingmaterial 35 held in place by the; stufling box bushing 36 pressed downby bolting means 37 A number of bolts 38 screwed into the block 33 areextended upward to adjustably support a table piece 39 held rigidly inplace on these bolts.

Positioned above this support 39 and rigidly fastened to the handle 31and rod 29 is a cross arm 40 carrying a pin 41 adapted to pass intoapertures 42, 43 and 44 of the support 39 beneath, these apertures beingso positioned that when the in 41 registers with either of them the knie switch 22 will register with the correspondin lead ter1ninal 12, 13 or14 ,within the ta :The rod 29 moves vertically through the cover 5 sothat by lifting the handle 31 the p of the apparatus in two main pin 41and knife switch 22 are removed from the corresponding recess 42," 43 or44 and terminal 12, 13 or 14. The handle 31 is then turned to bring the-pin41 into re 'ster with one of the other recesses and the nife bladecorrespondingly. moves into position to enter between theleaves 23 ofthe desired terminal 12, 13 or 14. Then upon depressing the handle 31the pin 41 enters its re-- cess and the knife switch 22 enters the nextcontact at the corresponding terminal so as to. change the tapconnection. A pivoted latch 43 may be provided en ing under the support39 to normally hold tie movable parts in depressed position. In order tochange the connection from one tap to the other it will then benecessary to release this latch 43. Where it is desired to make thedevice secure against change from one tap to mothers bolt 44 betweencross arm 40 and support 39 may be used to hold the movable partsagainst upward movement. The pin 41 is made sufiiciently lon so thatwhen it is' withdrawn from the ho e 42, 43 or 44 the knife switch bladewill be clear of the leaves 23 of the terminal 12, 13 or 14, and theswitch connection is thus made or broken by yertical movement of theblade.

With "the tap changer 'otthis invention the shift from one tap toanother is controlled entirely fromoutsideot the tank while the actualswitch connections are closed or opened within the tank and preferablybelow the surface of theioil-l It is not necessary therefore to openthegtank at any timeduring'the changing. The formation 1 arts with theconnection which an be 0 any desired length ermits the switch means tobe convenient y placed in any desired" position in the tank. When thetank cover 5 is to be removed the interior and exterior means may bedisconnected by withdrawing bolt 26 or 28 so that the switch means .ofthe ta changer may be left in set position on t e slab 11 and thecontrol means in la'ce on the cover. Then upon replacing e cover 5 it isonly necessary to reinsert the removed bolt and the. tap changer will beagain ready for use.

While the invention has been described in connection with a specificembodiment having three tap termlnals, it is obvious that any desirednumber of tap terminals may be provided to be connected and disconnectedin the manner shownand the invention is not confined to the detailsshown but is intended to cover any modifications there of falling withinthe scope of the appended claims. v

v I claim:

1. The combination with a container for electrical apparatus, of asupport in fixed position within said container arelatively movableswitch member carrie by said support and engaging tap terminals fromsaid apparatus, a removable cover for said container, a relativelymovable actuating means carried by said cover and a detachableconnection between said actuating means and said switch member adaptedto be disengaged to permit the cover to be removed without disturbingsaid switch member.

2. The combination with a container for electrical apparatus, of asupport in fixed position within said container, a relatively movableswitch member carried by said support and engaging tap terminals fromsaid apparatus, a removable cover for said container, a relativelymovable actuating means carried by said cover and extending outsidethereof, and a detachable connection between said actuating means andsaidswitch member adapted to be disengaged to permit the cover to beremoved without disturbing said switch member or said actuatingmechanism.

3. In a tap changer for transformers the combination with an interiorswitching means adapted to be positioned within av transformer tank andhaving a switch mem-' ber movable linearly into and out of contact withtap'terminals and rotatably to change from one terminal to another, ofcontrol means for said switch member adapted to be positioned outside ofthe transformer tank, and detachable connecting means between saidcontrol means and said switch member, said control means comprising amember movable with said switch member and a fixed member adapted toreceive and hold said movable member when said switch is in position tomake contact with one of said tap terminals." 4-

4. The combination with a tank, a transformer therein, a cover for saidtank and a tap changer for said transformer comprising switching meansin said tank control means therefor on said cover and a detachableconnection between said switching and control means to permit removal ofsaid cover without disturbing the positions of either of said means.

5. The combination. with a tank, a transformer therein, a cover for saidtank, of a tap changer for said transformer comprising circuit closingmeans in the tank, operating means therefor on the cover and adetachable connection between said circuit closing and operating meansto permit the removal of said cover without disturbing the positions ofeither of saidmeans and a device engaging said operating means to locksaid tap c anger in any of its circuit closing positions.

6. A tank adapted to contain electrical apparatus', a sheet metal coverfor said tank formed with a stutling box, a tap changer for saidelectrical ap aratus com rising switching'means locate within said tankand opcrating means comprising a rod slidable through said stuffing boxto switching means to open circuit position, a plate mounted on saidstufiin box and a latch on said operating means adapted to engage saidplate to prevent movement of said rod to circuit opening position.

7. In a tap changer for transformers the combination with an interiorswitching means adapted to be positioned within a move said transformertank and having tap terminals and a switching member movable linearlyinto and out of contact with said terminals and rotatably to change fromone terminal to another, of control means for said switch to theengaging positions of said switching member.

SAMUEL HORELIGK.

